Reactions of aryl diazonium salts and alkyl arylazo ethers. XI. Further evidence for the mechanism of dediazoniation in basic alcoholic solution

Abstract

A comparison of the relative amounts of dediazoniation, S_NAr and aryne reactions of 4-chloro-3- nitrobenzenediazonium ion with methoxide ion in CH₃OH and in CD₃OH confirms that the dediazoniation reaction involves hydride abstraction from the alkoxide ion by the electrophilic terminal nitrogen atom of the diazonium ion. Furthermore, the relative amounts of anionic and free-radical dediazoniation are the same in CH₃OH and in CD₃OH. This confirms that the partitioning between the free-radical and anionic pathways for dediazoniation is on the aryl diimide and not on the free diazonium ion.

Some previously reported results on the solvent effect (methanol against ethanol) for the reaction have been reinterpreted in the light of the above conclusions.